ISSN:
1434-6036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A system described by the Dicke Hamiltonian is considered. It is known that for the canonical density operator describing such a system, the internal energyU is strictly negative. On the other hand, the microcanonical density operator can be defined for an arbitrary value ofU. The thermodynamic limit for the microcanonical density operator is investigated. In the caseU〈0 the obtained results are completely equivalent to those of the canonical density operator. However, in the caseU〉0 it turns out that the photon density is non-zero, and that the entropy and the mean spin are independent ofU. Moreover, forU〉0 the coupling constant of the Hamiltonian does not appear in any thermodynamic formula after the thermodynamic limit is performed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01328861
